1. Field of the Invention
The present invention relates to a hand lever device for a working machine such as a hedge trimmer or brush cutter. In particular, it relates to a grip structure of such a hand lever device mounted on a handle of a working machine.
2. Description of the Prior Art
In general, in a conventional working machine such as a hedge trimmer and brush cutter which comprises an operative portion including a cutting blade driven by an internal combustion engine, a grip and a hand lever device are mounted on a U-shaped handle, a bar handle or the like of the working machine so as to provide manual control of output force of an internal combustion engine. Such a hand lever comprises a lever for controlling the degree of opening of a throttle valve of the internal combustion engine and a switch for stopping the internal combustion engine.
Japanese Patent Application No. 192575/1996 by the Assignee of the present application discloses a hand lever device (see FIG. 8, which is a left external side view, and FIG. 9, which is a sectional view taken along the line IX--IX and viewed in the direction of arrows in FIG. 8).
The hand lever device 10' has a case 20' fixedly mounted on a handle 7' in the vicinity of a proximal grip 11'. In the case 20', a main lever 30' has its one end pivotally held for drawing a throttle cable 17' extending through and within an outer tube 16' of a Bowden cable 15' connected to a throttle valve of an internal combustion engine. In a center portion of the top of the case 20', a slide type cut-off switch 50' is provided for short-circuiting an electrical circuit to a spark plug of the internal combustion engine to stop the engine.
As shown in FIG. 9, the Bowden cable 15' and a conducting cord 18' for the cut-off switch 50' are backward led through a relatively large through hole 19' formed in a lower portion of the proximal grip 11' and connected to the internal combustion engine.
The main lever 30' pivotally held by the case 20' comprises a substantially straight operating portion 31' pivotally operated by an operator's hand in such a manner that it is brought closer to a lever rest 11c' formed as a protuberant portion in the bottom of the proximal grip 11'. By pivotally operating the operating portion 31' to bring it closer to the lever rest 11c' at the bottom of the proximal grip 11', the throttle cable 17' extending through and within the outer tube 16' of the Bowden cable 15' is drawn to move the throttle valve of the internal combustion engine in the more wide open direction. Output force of the internal combustion engine is thereby increased.
In ordinary operation of the working machine, the hand lever device 10' is used to carry out the operation in such a manner that the proximal grip 11' is gripped by the operator's hand with the operating portion 31' in contact with the lever rest 11c' formed in the bottom of the proximal grip 11'.
Accordingly, in the hand lever device 10', the proximal grip 11' and the operating portion 31' are collectively gripped by the operator's hand to carry out the operation. However, in and through the proximal grip 11' between the handle 7' and the operating portion 31', the Bowden cable 15' and the conducting cord 18' are led. This results in a large diameter of the collective gripping. Since the proximal grip 11' and the operating portion 31' are firmly and continuously gripped by the operator during the operation, the gripping is heavy burden on the operator's fingers to cause a problem in operability.
Further, the Bowden cable 15' and the conducting cord 18' are inserted together through a single through hole 19' which is relatively large-sized so as to facilitate the insertion of the line members into the proximal grip 11'. Accordingly, the Bowden cable 15' and the conducting cord 18' tend to move freely in the through hole 19' in the horizontal direction. This causes a disadvantage that these line members are not stably held in the through hole 19'.